T-Mobile’s Xperia Z1s started receiving Android 5.0.2 Lollipop. The original Xperia Z1 received this update almost a month ago. It took way long for T-Mobile to rollout the latest firmware for its Sony Xperia Z1s users. New update moves the build number from 14.4.B.0.56to 4.5.B.0.236. This update brings all the Lollipop goodies including Material Design, enhanced security, stability, better battery life, notifications on lock-screen and some other features for the Xperia Z1s. At the moment, it is being rolled out to users through OTA or through Sony PC Companion. But if you haven’t received this update yet and you want to update your Xperia Z1s manually, this guide is going to help you out.

As we move forward, we will install this latest Android 5.0.2 Lollipop firmware with the build number 4.5.B.0.236 on our beloved T-Mobile Xperia Z1s C6916. We will use Sony’s flashtool to flash FTF file of the firmware. While you flash this firmware, please be noted that this is the official firmware and it is untouched. It will not void the warranty of your device or result in causing any damage to your device.

Let’s go ahead and install Lollipop on your T-Mobile Xperia Z1s now.

1. This is only for T-Mobile Sony Xperia Z1s C6916

This ROM is only for the device mentioned above. Make sure that your model number matches the one listed above. To do so, go to Settings > About Device on your device and see your model number. Flashing this firmware on any other device will result in bricking it so make sure that you meet this requirement first of all.

2. Battery should be charged at least over 60%.

Make sure that your battery is charged enough to complete the flashing process. In case your battery is low and your device goes dead during the flashing process, you may end up soft bricking your device as it won’t complete the flashing process.

3. Backup everything!

Just to be on the safe side, you may consider backing up each and everything from your Android device. This is highly recommended so that in case anything goes wrong, you still have the access to all of your data and you can restore it immediately. You may backup everything as listed below.

Enable USB debugging mode on your device. To do so, tap settings>developer options>USB debugging. If you can’t find developer options in settings, then tap settings > about device and tap “Build Number” for 7 times and you’ll get em’ activated under settings.

After installing Sony Flashtool, open the Flashtool folder from the drive where you installed it. Now open Flashtool>Drivers>Flashtool-drivers.exe and install the Flashtool, Fastboot & Xperia Z1s drivers from the list. [Important]

6. Use OEM data cable to establish connection.

Make sure that you use the phone’s original data cable to establish connection between your phone and the PC. Using a different data cable might result in interrupting the firmware installation.